The present disclosure relates to transducers for converting between electrical energy and mechanical energy and to methods of making transducers.
Means of converting between electrical energy and mechanical energy (e.g., actuators and generators) are utilized in microscale and macroscale tranducers, sensors, motors, pumps, artificial muscles, robotics, computer components, and prosthetic devices. For automotive applications, nearly every vehicle produced today, from light vehicles to heavy duty construction equipment, includes a plethora of sensors and actuators that monitor and control the operation of the vehicle. Common actuation technologies include electromagnetic motors and solenoids. In some cases, such as when the device is small in size (micro- or meso-scale devices), in lightweight devices, or in single structures incorporating a large number of devices, such technologies are not suitable. Alternative actuation or generation technologies include so-called “smart materials” such as piezoelectric ceramics, magnetostrictive materials, shape memory alloys, and electroactive polymers. While suitable for their intended purpose, some drawbacks to these materials may include low strain values, high density, low efficiency, slow response, processing difficulties, and high cost.
More recently, improvements in actuation and generation technology have been disclosed in WO 01/06575 and WO 01/58973. These references demonstrate electric field-induced deformation of an actuator containing an elastomeric dielectric material and compliant electrodes. Suitable elastomers include acrylate and polysiloxane-based polymers. Such actuators have high strain values, fast response times and high electromechanical efficiency. Strain refers to the changes in the thickness and/or area of the actuator upon application of an electric field. Some drawbacks, however, include low tear strength for polysiloxane polymers and slow response times for acrylate polymers.
There thus remains a need for improved transducers and methods of making the transducers.